fix(interpreter): keep the return value across deferred user calls

packages/interpreter/tests/program_eval_test.zigmodified+173-0

Changes to packages/interpreter/tests/program_eval_test.zig

		⋯98 linesShow the 98 lines above this hunk@@ -99,3 +99,176 @@ test "eval: runaway user recursion returns a runtime error" {
99	99	\\}
100	100	));
101	101	}
	102	+
	103	+test "eval: deferred user function calls keep the pending return value" {
	104	+ try runProgram(
	105	+ \\struct Box {
	106	+ \\ v: int,
	107	+ \\}
	108	+ \\
	109	+ \\impl Box {
	110	+ \\ fn get(self): int {
	111	+ \\ defer cleanup()
	112	+ \\ return self.v
	113	+ \\ }
	114	+ \\}
	115	+ \\
	116	+ \\fn cleanup() {
	117	+ \\}
	118	+ \\
	119	+ \\fn direct(): int {
	120	+ \\ defer cleanup()
	121	+ \\ return 7
	122	+ \\}
	123	+ \\
	124	+ \\fn in_if(): int {
	125	+ \\ if true {
	126	+ \\ defer cleanup()
	127	+ \\ return 8
	128	+ \\ }
	129	+ \\ return 0
	130	+ \\}
	131	+ \\
	132	+ \\fn in_else(): int {
	133	+ \\ if false {
	134	+ \\ return 0
	135	+ \\ } else {
	136	+ \\ defer cleanup()
	137	+ \\ return 9
	138	+ \\ }
	139	+ \\ return 0
	140	+ \\}
	141	+ \\
	142	+ \\fn in_while(): int {
	143	+ \\ while true {
	144	+ \\ defer cleanup()
	145	+ \\ return 10
	146	+ \\ }
	147	+ \\ return 0
	148	+ \\}
	149	+ \\
	150	+ \\fn in_range_loop(): int {
	151	+ \\ for i in 0..3 {
	152	+ \\ defer cleanup()
	153	+ \\ return i + 11
	154	+ \\ }
	155	+ \\ return 0
	156	+ \\}
	157	+ \\
	158	+ \\fn in_array_loop(): int {
	159	+ \\ for x in [12] {
	160	+ \\ defer cleanup()
	161	+ \\ return x
	162	+ \\ }
	163	+ \\ return 0
	164	+ \\}
	165	+ \\
	166	+ \\fn in_block(): int {
	167	+ \\ {
	168	+ \\ defer cleanup()
	169	+ \\ return 13
	170	+ \\ }
	171	+ \\ return 0
	172	+ \\}
	173	+ \\
	174	+ \\fn main() {
	175	+ \\ let closure = fn(): int {
	176	+ \\ defer cleanup()
	177	+ \\ return 14
	178	+ \\ }
	179	+ \\ let box = Box { v: 15 }
	180	+ \\ assert(direct() == 7)
	181	+ \\ assert(in_if() == 8)
	182	+ \\ assert(in_else() == 9)
	183	+ \\ assert(in_while() == 10)
	184	+ \\ assert(in_range_loop() == 11)
	185	+ \\ assert(in_array_loop() == 12)
	186	+ \\ assert(in_block() == 13)
	187	+ \\ assert(closure() == 14)
	188	+ \\ assert(box.get() == 15)
	189	+ \\}
	190	+ );
	191	+}
	192	+
	193	+test "eval: a value left behind by a call inside a defer does not replace the pending return" {
	194	+ try runProgram(
	195	+ \\fn noop() {
	196	+ \\}
	197	+ \\
	198	+ \\fn cleanup() {
	199	+ \\ let c = fn(): int {
	200	+ \\ return 99
	201	+ \\ }
	202	+ \\ c()
	203	+ \\ defer noop()
	204	+ \\}
	205	+ \\
	206	+ \\fn outer(): int {
	207	+ \\ defer cleanup()
	208	+ \\ return 7
	209	+ \\}
	210	+ \\
	211	+ \\fn main() {
	212	+ \\ assert(outer() == 7)
	213	+ \\}
	214	+ );
	215	+}
	216	+
	217	+test "eval: a return inside a deferred block still sets the returned value" {
	218	+ try runProgram(
	219	+ \\fn final_return(): int {
	220	+ \\ defer {
	221	+ \\ return 5
	222	+ \\ }
	223	+ \\ return 7
	224	+ \\}
	225	+ \\
	226	+ \\fn earlier_return(): int {
	227	+ \\ defer {
	228	+ \\ return 6
	229	+ \\ 0
	230	+ \\ }
	231	+ \\ return 7
	232	+ \\}
	233	+ \\
	234	+ \\fn main() {
	235	+ \\ assert(final_return() == 5)
	236	+ \\ assert(earlier_return() == 6)
	237	+ \\}
	238	+ );
	239	+}
	240	+
	241	+test "eval: deferred calls run in reverse order before the return value is used" {
	242	+ try runProgram(
	243	+ \\fn inner(): int {
	244	+ \\ defer note(1)
	245	+ \\ return 99
	246	+ \\}
	247	+ \\
	248	+ \\let mut order = 0
	249	+ \\
	250	+ \\fn note(n: int) {
	251	+ \\ order = order * 10 + n
	252	+ \\}
	253	+ \\
	254	+ \\fn first() {
	255	+ \\ note(2)
	256	+ \\}
	257	+ \\
	258	+ \\fn second() {
	259	+ \\ assert(inner() == 99)
	260	+ \\ note(3)
	261	+ \\}
	262	+ \\
	263	+ \\fn outer(): int {
	264	+ \\ defer first()
	265	+ \\ defer second()
	266	+ \\ return 7
	267	+ \\}
	268	+ \\
	269	+ \\fn main() {
	270	+ \\ assert(outer() == 7)
	271	+ \\ assert(order == 132)
	272	+ \\}
	273	+ );
	274	+}